We are trying to capture VLAN tagged packets on a Cisco Catalyst 3750. We have a VoIP phone that boots on our DATA VLAN and gets settings pushed to it from DHCP Scope option 242. One of these options tells the phone to boot on the VoIP VLAN.

Anyways, I've been doing a simple "monitor session" on the Cisco Catalyst for this but it doesn't appear we're seeing all of the VLAN tagged data. Our vendor suggests the best solution is to break out and use a hub. I tend to agree, but would like to know if I was over-looking a capture option on the Cisco platform.